The invention relates generally to an apparatus and a method for regulating a pressure in a chamber.
in FIG. 1, a prior art system is shown for generating a vacuum in a chamber, such as that used in the manufacturing or processing of semiconductor products, such as devices and wafers. The chamber 1 has a process gas injected at a flow rate of QHv. The pressure PHv in the chamber 1 is measured with the gauge or sensor 5, which generates the pressure signal P. To generate a high vacuum in the chamber 1, the intake side of a high vacuum pump 2 is coupled to the chamber 1. Typically, a turbo molecular pump is used as the high vacuum pump 2. Further, the intake side of a roots vacuum pump 3, which is a type of rotary blower, is coupled to the exhaust side of the high vacuum pump 2, and the exhaust side of the roots vacuum pump 3 is coupled to the intake side of a pre-vacuum pump 4.
In the prior art system of FIG. 1, the pressure PHv of the chamber 1 is regulated using the throttle valve 8. The pressure signal P corresponds to the pressure PHv of the chamber 1 measured with the gauge or sensor 5. Based on the pressure signal P, the system operator 6 manually or automatically determines a desired set point pressure for the chamber 1 and generates a set pressure signal Ps corresponding to the desired set point pressure. The set point pressure signal Ps is used by the controller 7 to generate a signal u, which is used to vary the cross-section of the throttle valve 8. In so doing, the pressure PHv of the chamber 1 is regulated, and a high vacuum within chamber 1 is achieved.